It is generally considered desirable to reduce the level of noise within a vehicle passenger compartment. External noises, such as road noise, engine noise, vibrations, etc., as well as noises emanating from within passenger compartments, may be attenuated through the use of various acoustical materials. Accordingly, sound attenuating materials for vehicles, such as automobiles, are conventionally used in the dashboard, in conjunction with carpeting for floor panels, in the wheel wells, in the trunk compartment, under the hood, and as part of the headliner.
Recently, a lot of emphasis has been placed on the acoustic properties of vehicle trim components, such as carpeting and dash insulators, because of customer requirements for quieter passenger compartments. Carpeting used to cover the floor areas of vehicles, such as automobiles, is conventionally molded into a non-planar three dimensional contoured configuration which conforms to the contours of the vehicle floor so as to fit properly. Dash insulators are mounted to a vehicle firewall which separates the passenger compartment from an engine compartment. Dash insulators are designed to reduce the transmission of noise and heat from the engine compartment into the passenger compartment. Package trays and trunk trim may be used to reduce the noise entering the passenger area of a vehicle.
A foam or fibrous layer of material referred to as a decoupler is typically attached to the backside of vehicle dash insulators and carpeting to assist in the sound attenuation. The decoupler may act as an isolator between adjoining layers. The decoupler and interior trim component are usually supplied for installation into the vehicle separately, but preferably as described herein, should be combined during manufacturing so that a single product may be installed in the vehicle, saving labor and transportation costs. Decouplers may be required to have complex shapes and configurations and, as such, may be time-consuming and expensive to manufacture. Vehicle manufacturers are constantly looking for ways to reduce costs and complexity associated with vehicle manufacturing. Moreover, vehicle manufacturers are constantly looking for ways to reduce noise within passenger compartments while reducing weight of trim components. Accordingly, there is a need for acoustical insulation materials for use within vehicles that exhibit superior sound attenuating properties, while also being lightweight, low in cost and easy to install.